Certificate of correction



H. J. CHALL May 12, 1959 SHOCK ABSORBING SELECTION MECHANISM FOR A CALCULATING MACHINE fiFiled April 12. 1954 United States Patent SHOCK ABSORBING SELECTION MECHANISM FOR A CALCULATING MACHINE Harold J. Chall, San Leandro, Calif., assignor to Friden, Inc., a corporation of California Application April 12, 1954, Serial No. 422,572

7 Claims. (Cl. 235-60) This invention relates to calculating machines, such as the ten-key, listing adding machine shown in my Patent No. 2,832,530, issued April 29, 1958, for Value Selecting and Transmitting Mechanism for Listing Adding Machine, and constitutes a division of, and an improvement on, the invention shown in the above-noted application.

In calculating machines, such as the adding machine shown in the above-noted application, utilizing a plurality of ordinally arranged selecting sectors angularly movable by spring force about a common shaft or axis to differentially set angular positions in response to the entry of a selected entry value into the selection mechanism of the machine, and a plurality of stop pins set by the machine keyboard to stop the selection sectors in such differentially set positions, there is a tendency for the selecting sectors to rebound or vibrate on striking the set stop pins, particularly the pins corresponding to the higher value digits, with a consequent tendency to cause the entry of erroneous values.

It is among the objects of the present invention to provide an improved selecting sector assembly for a calculating machine of the character indicated, which assembly is so constructed as to eliminate the rebound occasioned by a selecting sector impacting a set stop pin or to minimize such rebound to an extent such that it has no disadvantageous effect on the operation of the associated digitation mechanism; which selecting sector assembly includes a sector component and a live point component disposed at one end of the sector component to engage the stop pins which stop the assembly in selected digitation positions, each live point being pivotally connected to the corresponding sector component in a manner to absorb energy of impact between the sector assembly and the stop pins; which may, if desired, utilize other means associated with the live point component for absorbing the energy of impact between the selecting sector assemblies and the stop pins; which does not materially change the positions of the selecting sector assembly as determined by the set stop pins; and which provides a quiet and accurate operation of the digitation mechanism with no substantial modification of the selecting sector assemblies.

Other objects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction with the accompanying drawings wherein;

Fig. 1 is a longitudinal cross-sectional view through the selection mechanisms of a ten-key calculating machine or calculating machine component, and

Fig. 2 is an elevational view of a live point component and associated portions of a selecting sector component shown in Fig. 1, illustrating structural details of the live point and selecting sector components.

With continued reference to the drawing, the digitation mechanism, as illustrated, comprises a cage, or carriage, generally indicated at 10, slidably mounted on vertically gentially to the circumference of the sector.

2,886,237 Patented May 12, 1959 spaced-apart guide rods 11 and 12 which extend transversely of the machine in substantially parallel relationship to each other and are supported at their opposite ends on vertically disposed side plates of the machine. A ten-key keyboard assembly, generally indicated at 14, is mounted on the frame side plates of the machine immediately in front of the front end of the cage 10, and an escapement mechanism 15, illustrated in detail in the patent mentioned above, is connected between the keyboard 14 and the cage 10 to step the cage transversely across the machine in a direction from right to left as the keys of the keyboard are sequentially depressed, the cage being returned to its home, or full-cycle, position at the right-hand side of the machine frame during an operating cycle of the machine by mechanism, also fully disclosed in the above-referred-to patent.

A shaft 18 is supported at its ends in the side walls of the cage 10 and extends transversely across the cage rearwardly of, and parallel to, the guide rods 11 and 12. A plurality of ordinally arranged selection sector assemblies, generally indicated at 20, are mounted on the shaft 18 for angular, or rotational, movement about the shaft 18, which constitutes a common rotational axis for all of the selecting sector assemblies.

Each selecting sector assembly 20 comprises a hub 22 rotatably mounted on the shaft 18, spoke structures 23 and 24 projecting radially from the hub at substantially diametrically opposite positions around the hub, a pcripheral dial 25 carried on the outer edge of the spoke structure 23 and having a partly cylindrical outer surface provided-with numerals consecutively arranged from 0 to 9 spaced apart longitudinally of the dial, an arcuate rim 26 at the outer end of the spokestructure 24, arranged concentrically of the axis of shaft 18 and provided on its outer edge with a series of gear teeth 28, and a peripherally grooved sheave 29 disposed at one side of, and concentrically of, the hub 22. A tie rod 30 extends transversely of the cage 10 parallel to, and rearwardly of, the shaft 18 and is disposed adjacent the outer edges of the sheaves 29 of the selecting sector assemblies. Springs 32 extend one around each of the sheaves 29, one end of each spring 32 being connected to a stud 33 carried by the spoke structure 24 of the corresponding selecting sector assembly and extends from the stud 33 upwardly and rearwardly over the sheave 29, being connected at its other end to the tie rod 30, these springs resiliently urging all of the selecting sector assemblies to turn about the shaft 18 in a clockwise direction, as viewed in Fig. 1.

The rack portion 26 of each selection sector assembly 20 has an upper end and a lower end and has on its lower end an extension 35 disposed substantially tan- Each selection sector also includes an ear 36 projecting radially from the hub 22 toward the end of the extension 35, on which a live point, generally indicated at 38, is pivotally connected at one end to the ear 36 by a rivet 39 secured to the ear 36 and projecting laterally therefrom. At its other end the live point 38 is provided with a nose formation 40, which extends in a direction away from the adjacent end of the extension 35 of the rack portion of the selecting sector, and the live point is resiliently held against the adjacent end of the extension 35 by a tension spring 42 connected between the live point at a location intermediate the length thereof and the spoke formation 24 of the sector.

The live point 38 is a fiat element having a shape somewhat resembling an S, and is disposed outwardly of the end of the extension 35, except for an arm 43 of the live point which projects from the edge of the live point element nearest the distal end of the extension 35, and

ing movement of the live point about its pivotal connection with the ear 36. A guide clamp 44 is secured to the arm 43 and straddles the adjacent portion of the extension 35 to guide the live point in its rocking movements relative to the associated selecting sector.

A pin cage, generally indicated at 45, of rectangular cross-sectional shape, constitutes a portion of, and is disposed at, the forward side of the carriage and includes spaced-apart and substantially parallel outer and inner plates 46 and 47. The plates 46 and 47 are provided with spaced-apart apertures arranged in a predetermined pattern. Stop pins, as indicated at 48, extend slidably through mutually registering apertures in the plates 46 and 47, these pins being arranged in rows transversely of the pin cage with the rows equal in number to the number of selecting sector assemblies. Each row extends between the bottom and top of the pin cage and includes eight stop pins corresponding to the digits 1 to 8, inclusive.

It will be noted that the lower guide rail 12 extends below the lower portion of the pin cage 45, and that a shaft 50 extends through the pin cage between the front and rear plates thereof, above, and parallel to, the guide rail 12, this shaft 50 being disposed in the lower portion of the pin cage and being supported at its ends on the side plates of the carriage 10. Zero latch levers 52, equal in number to the number of ordinally arranged selecting sector assemblies 20, are pivotally mounted intermediate their lengths on the shaft 50, one end of each lever 52 extending through the inner plate 47 toward the corresponding selecting sector, and the other end extending through the outer plate 46 for a purpose to be presently described. A spring 54 is connected between the portion of each zero latch lever 52 extending through the outer plate 46 and a tie bar 55 extending across the carriage adjacent to, and substantially parallel to, the bottom guide rail 12. These springs resiliently urge the zero latches 52 to their sector latching position, as illustrated in Fig. 1, in which the upper edge of the portion of each lever 52 extending through the inner pin cage plate 47 bears against the upper end of the slot provided in this plate for the extension of the corresponding portion of the zero latch lever therethrough.

When the selecting sector assemblies and the zero latch levers are in their home or full-cycle position, as illustrated in Fig. 1, the nose formations 40 of the live point components 38 of the selecting sector assemblies bear against the adjacent ends of the zero latch levers 52, so that the zero latch levers releasably latch these selecting sector assemblies in their 0 position against the force of springs 32.

The keyboard 14 has a frame, or support, structure, including a pair of horizontally disposed plates 58 and 59, which are substantially parallel to each other in vertically spaced-apart relationship and are supported by vertical plates, one of which is indicated at 60. The horizontal plates 58 and 59 are provided with spacedapart slots arranged in a predetermined pattern. The flat key stems 62 of nine digit keys extend slidably through mutually registering apertures in the plates 58 and 59 for vertical movement of the keys longitudinally of the key stems. The machine may also include a 0 key and various control keys as more fully shown and described in my patent referred to above.

A Zero latch control bar 63 extends longitudinally of the keyboard and medially of the width thereof between the plates 58 and 59 and at its rear end this bar is operatively connected to the escapement mechanism 15. Each key stem 62 is provided with a laterally projecting offset 64 which extends over the bar 63 so that this bar will be forced downwardly to operate the escapement mechanism and step the shiftable selecting mechanism one step to the left each time a digit key is depressed. The 0 key of the keyboard also operates the escapement mechanism to step the shiftable selection mechanism one step to the left each time the 0 key is depressed, but operation of the 0 key does not actuate any of the digitation mechanism except the escapement.

A lever 65, extends longitudinally of the keyboard be low the bottom horizontal plate 59 and is pivotally mounted intermediate its length on a stud 66 supported by the keyboard frame and has, at its forward end, an upwardly extending offset 67 which underlies the bar 63 near the front end of this bar. This lever 65 is pivotally connected at its rear end by a pivotal connection 68, to the upper end of a link 69, which is inclined downwardly and rearwardly from the pivotal connection 68 in front of, and substantially parallel to, the outer plate 46 of the stop pin cage 45. At its lower end the link 69 is pivotally connected by a connection 70 to a zero latch actuating dog 71, pivotally mounted forwardly of the link 69 on the base, not illustrated, of the machine.

A plate 72, fixed to the keyboard frame and extending transversely of the machine and substantially parallel to the plate 46, is disposed between the link 69 and the plate 46 and is provided near its lower end with a slot 73, through which the end portion 74 of the dog 71, extending rearwardly from the pivotal connection 70, projects. The portion 74 of the dog 71 underlies the forward end of the zero latch 52 disposed in alignment with the dog. Thus, when a digit key of the keyboard 14 is depressed, rocking the lever 65 in a counter-clockwise direction, as viewed in Fig. 1, the link 69 is raised, moving the rearward end portion 74 of the dog 71 upwardly against the lower corner of the forward end of the aligned zero latch lever 52 and rocking the zero latch lever in a clockwise direction, as viewed in Fig. 1. Such rocking of the latch lever moves the rear end of the zero lever out of engagement with the front end of the nose formation 40 of the live point component 38 of the selecting sector assembly in alignment with the zero latch lever releasing dog. When the Zero latch lever 52 releases the live point component of the corresponding selecting sector assembly, the associated spring 32 turns the selecting sector assembly in a clockwise direction, as viewed in Fig. 1, until the sector is stopped by a selectively set stop pin 48 in the row of stop pins of the same order as the order of the released selecting sector, or by a fixed stop, not shown herein, but actually mounted on the tie bar 75 in the event the 9 key has been depressed.

A plurality of bellcrank levers 78 are pivotally mounted at their angles on a stud, or shaft, Stl extending transversely of the keyboard below the bottom horizontal plate 59 and near the rear edge of this plate. Each of these bellcrank levers has a forwardly projecting arm 81 provided at its forward end with an upwardly directed oifset portion 82 which underlies the bottom end of a plunger portion 84 of a corresponding digit key stem 62 extending through a slot in the bottom horizontal plate 59 so that when any one of the digit keys is manually depressed, the corresponding bellcrank lever '78 is rocked about the shaft in a counter-clockwise direction, as viewed in Fig. 1.

The key stems are resiliently urged to their raised position by suitable compression springs 86, respectively surrounding the lower portions of the key stems above the plate 59 and bearing at their upper ends against shoulders provided on the key stems. Also, the bellcrank levers 78 are resiliently urged to their retracted, or fullcycle, position by tension springs 87 provided one for each of the bellcrank levers. A fixed bracket 88 is inclined downwardly and rearwardly from the stud 66 to the bottom end of the plate 72 and has a flat rearward surface 89 disposed parallel to the plate 72. Each of the bellcrank levers is provided near its lower end with a forwardly projecting nose formation 90, the front end of which bears against the flat rear surface of the bracket 88 when the lever is in its retracted position, each of the springs 87 being connected at one end to an apertured tongue 91 laterally offset from the nose formation of the corresponding lever at a location spaced rearwardly from the bracket 88 and being connected at its other end to the bracket 88, so that the bellcrank levers 78 are resiliently urged to their retracted position in which the forward ends of the nose formations 90 thereof bear against the rearward surface of the bracket 88.

The bellcrank levers 78 are provided with rearwardly and downwardly extending arm 94, which arm is laterally bent, or offset, so that the rearward ends of all such levers extend through a slot 95 provided in the plate 72 and lying in a single plane extending longitudinally of the associated machine and perpendicular to the machine base. The slot 95 is directly above the aperture 73 and the rearward ends of the bellcrank lever arms 94 are disposed, one above the other, in the slot 95 of the plate 72. These bellcrank levers are so associated with the digit keys that when the 1 digit key is manually depressed, the lowermost of the bellcrank lever arms 94 is moved rearwardly through the slot 95 and against the forward end of the lowermost stop pin 48 of the ordinal row of stop pins in alignment with the slot 95. The second bellcrank arm 94 from the bottom corresponds to the 2 digit key and the remaining lever arms 94 correspond in order to the digit keys 3 to 8, inclusive, the uppermost lever arm 94 being forced rearwardly through the slot 95 when the 8 digit key is depressed to engage the forward end of the uppermost stop pin 48 and move this stop pin rearwardly. Depression of the 9 digit key releases the latch lever 52 and frees the selector sector assembly to stop against a fixed stop, not shown.

The timing of the mechanism is such that when a digit key of the keyboard is depressed the corresponding stop pin 48 is first moved rearwardly to its projected, or operative, positionand the zero latch lever 52 of the same order is then rocked to release the corresponding selecting sector assembly for clockwise movement by the associated spring 32. The spring 32 then turns the corresponding selecting sector assembly until the leading end of the nose formation 40 of the associated live point 38 strikes the lower edge of the rearward end portion of the set stop pin 48 to stop the movement of the selecting sector assembly at an angular position corresponding to the number of the digit key which was depressed to accomplish this operation.

As digit keys are successively depressed, selecting sector assemblies from the left-hand toward the right-hand end of the ordinally arranged group of such assemblies are released and differentially set to rotational positions corresponding to the successively depressed keys and are simultaneously stepped to the left, so that a number of selecting sector assemblies equal to the number of digits in the value entered by the depression of the keyboard keys, will be differentially set to angular positions corresponding to the selected digits and will be stepped to the left of the home, or full-cycle, position of the leftmost selecting sector assembly of the group. After the selecting sector assemblies have been differentially set and stepped to the left, as indicated above, other mechanisms of the machine can be operated to enter the selected entry value from these activated selecting sector assemblies to the printing mechanism and accumulator mechanism of the machine, as set forth in patent referred to above. As the value is being entered, as indicated above, the selector sector assemblies which have been differentially set, are restored to their position, return movement of the sectors being limited by engagement of the spoke structures with a fixed stop bar 75 extending longitudinally of the cage 10. Simultaneously, shiftable unit including the carriage 10, and the pin cage 45, the selector sector assemblies 20 and the stop pins 48, is returned to its home, or full-cycle, position; and, during this return of the shiftable unit, the stop pins which have been. set by. the keyboard. are. retracted to 6 their full-cycle position by the retracting bars 98 in a well-known manner.

In selecting sector assemblies of the character indicated above, as previously used, the live point components 38 are provided with straight rear edges which bear against the full lengths of the straight front ends of the extensions 35 of the rack portions 26 of the corresponding selecting sectors. Each previous live point was provided with a. round aperture which closely receives the rivet 39 which pivotally connects the live point to the corresponding sector. When the associated spring 42 pulled the live point back against the front end of the sector extension 35, there was a solid connection between the live point and the sector extension. With this construction, it has been found that when the leading end of the nose formation 40 of the live point component of the assembly strikes a set stop pin 48, particularly one of the upper stop pins corresponding to a digit of higher value, there is a tendency for the selecting sector assembly to rebound one or more times before coming to rest at the angular position determined by the selection of the set stop pin. If a control key in the machine is actuated while the selecting sector assembly is at an angular position to which it has rebounded from the set stop pin, the setting of the selecting sector assembly will not be correct for the entry of the desired digit value into the machine and an erroneous entry may occur. If, on the other hand, the operator waits for the rebounding or vibratory movement of the sectors to subside before making the entry, this will to some extent reduce the maximum operating speed of the machine. This rebounding of the selecting sector assemblies may also produce an unfavorable condition for the meshing of the actuating or transmission gears of the machine with the gear teeth 28 of the rack portions 26 of the selecting sector assemblies, and it is thus highly desirable that any tendency of the selecting sector assemblies to rebound when the live poiut components thereof impact set stop pins, be eliminated or at least reduced to an inconsequential amplitude.

In accordance with the present invention the portion of the rear edge of each live point component 38 opposed to the front end of the rack extension 35 of the corresponding sector component, is cut away on an angle, as indicated at 100, so that the rear edge of the live point engages the front end of the corresponding extension 35 substantially with a point contact 101 near the inner corner of the extension, which contact serves as a fulcrum for a limited rocking movement of the live point component relative to the associated sector component of the assembly. Also, the aperture in the live point component through which the rivet 39 extends, is elongated, as indicated in 102 in Fig. 2, in a direction such that when the corresponding spring 42 disposes the live point component against the rivet 39 and the front end extension 35, a space is provided between the rivet and the end of the elongated aperture at the lower, rear side of the rivet, the medial location of this space being approximately on a line extending through the center, or axis, of rivet 39 and inclined rearwardly and downwardly at an angle of approximately 45 degrees to the horizontal, as viewed in Fig. 2. This fulcrum contact 101 between the live point and the extension 35 and the elongation of the rivet receiving aperture in the live point component provides a limited freedom of rocking movement of the live point component relative to the associated selecting sector component, so that the live point component can rock a limited amount relative to the sector component by which it is carried against the force of spring 42 when the leading end of the nose formation 40 of the live point component impacts a set stoppin. This slight, resiliently resisted, movement of the live point component relative to the carrying sector component absorbs the energy of impact of the live point with a set stop pin to a sufiicient extent to substantially eliminate the rebound of the selecting sector assemblies and, as the live point component is immediately restored to its normal position relative to the associated sector component by the spring 42, the selecting sector assembly is substantially immediately stopped at the angular position at which the leading end of the nose formation 40 of the live point component strikes the set pin 48.

The rebound damping efiect of the modified live point component structure is also enhanced by the fact that the angular position of the elongation of the rivet receiving aperture in the live point component is such that a slight sliding movement is produced between the contacting portions of the rear edge of the live point component and the front end of the sector component extension 35 which adds a frictional damping effect to the action of the live point component.

While the modification of the live point component of each selecting sector assembly, as illustrated in the accompanying drawing and described above, has been found effective to dampen the rebound tendency of the selecting sector assemblies by absorbing the energy of impact between the live point components and the set stop pins, it is to be understood that the invention is not limited to this particular arrangement but that other means may be provided within the scope of the invention to provide a damping effect at the instant of impact of a live point component with a set stop pin such, for example, as by slightly changing the shape of the nose formation 40 of the live point and the end portions of the stop pins engaged by the live point to provide a frictional damping effect at, or immediately prior to, the sector stopping impact; or by, providing for a limited, resiliently resisted swinging movement of the stop pins instead of, or in combination with, the above-described limited freedom of rocking movement of the live point components relative to the sector components of the selecting sector assemblies.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

What is claimed is:

1. In a selection mechanism including a plurality of ordinally arranged selecting sector assemblies mounted for angular movement about a common axis and each including a sector component and a live point component rockably mounted at one end on said sector component at one end of the latter, springs resiliently urging said selecting sector assemblies to move in one direction about said common axis, latch means adapted to engage said live points for releasably latching said selecting sector assemblies against movement by the last-named springs, and stop pins disposed adjacent said selecting sector as semblies and selectively settable to engage said live point components and thereby stop said selecting sector assemblies when released from said latch means at differentially set positions for the entry of selected values into said selection mechanism, the combination which comprises a fulcrum means between said live points and the ends of their respective sectors, a pin-and-slot mounting for said live points on their respective sectors to provide for rocking of the live point around said fulcrum as well as around its mounting, a resilient means biasing said live points into engagement with the ends of their respective sectors and opposing rocking movement of the live point around said fulcrum, to thereby cushion the shock of impact of a selecting sector assembly with a set stop pin and thereby dampen the tendency of the selecting sector assembly to rebound.

2. In a selection mechanism including a plurality of ordinally arranged selecting sector assemblies mounted for angular movement about a common axis and each including a sector component, springs resiliently urging said selecting sector assemblies to move in one direction about said common axis, latch means releasably latching said selecting sector assemblies against movement by the last-named springs, stop pins, disposed adjacent said selecting sector assemblies and selectively settable to engage said sectors and thereby stop said selecting sector assemblies when released from said latch means at differentially set positions for the entry of selected values into said selection mechanism, and a keyboard disposed adjacent said stop pins for releasing said latch means and selectively setting said stop pins, the combination which comprises a live point component pivotally and slidably mounted at one end on said sector component at one end of the latter in a manner to be interposed between the sectors and their respective stop pins, and a live point retracting spring resiliently holding said live point component against said one end of said sector component, whereby said live point components have a limited freedom of rocking movement relative to the associated selecting sector component in a direction against the force of said live point retracting spring and in the direction in which the live point component is urged by impact thereof with a stop pin to thereby cushion the shock of impact of a selecting sector assembly with a set stop pin and thereby dampen the tendency of the selecting sector assembly to rebound.

3. A selection mechanism comprising a plurality of ordinally arranged selecting sector assemblies mounted for angular movement about a common axis and each including a sector component, a live point component mounted on said sector component adjacent one end of the latter for limited rotation about two pivot points with respect to the respective sector component and spring means for holding the live point against the two pivot points, springs resiliently urging said selecting sector assemblies to move in one direction about said common axis, latch means releasably latching said selecting sector assemblies against movement by the last-named springs, and stop pins disposed adjacent said selecting sector assemblies and selectively settable to engage said live point components and thereby stop said selecting sector assemblies at differentially set positions when released from said latch means for the entry of selected values into said selection mechanism.

4. In a selection mechanism including a plurality of ordinally arranged selecting sector assemblies mounted for angular movement about a common axis and each including a sector component, springs resiliently urging said selecting sector assemblies to move in one direction about said common axis, latch means releasably latching said selecting sector assemblies against movement by the last-named springs, stop pins disposed adjacent said selecting sector assemblies and selectively settable to engage said sectors and thereby stop said selecting sector assemblies when released from said latch means at differentially set positions for the entry of selected values into said digitation mechanism, and a keyboard disposed adjacent said stop pins for releasing said latch means and selectively setting said stop pins, the combination which comprises a live point component mounted at one end thereof by a pin-and-slot mounting on each of said sector components at a point intermediate said axis and the ends of the sectors toward said stop pins and adapted to be interposed between that end of said sectors and said stop pins, a fulcrum between each live point and the said end of its respective sector, and a Live point retracting spring resiliently holding said live point component against said one end of said sector component, thereby providing a limited freedom of resiliently resisted movement thereof after initial contact thereof with a set stop pin to thereby cushion the shock of impact of said selecting sector assemblies against the said stop pins and dampen the, tendency of said selecting sector assemblies to rebound.

5. In a selection mechanism including a plurality of ordinally arranged selecting sector assemblies mounted for angular movement about a common axis and each including a sector component, a live point component movably mounted at one end on said sector component, and a live point retracting spring resiliently holding said live point component against said one end of said sector component, springs resiliently urging said selecting assemblies to move in one direction about said common axis, latch means releasably latching said selecting sector assemblies against movement by the last-named springs, and stop pins disposed adjacent said selecting sector assemblies and selectively settable to engage said live point components and stop said selecting sector assemblies when released from said latch means at differentially set positions for the entry of selected values into said selection mechanism, the arrangement wherein each of said live point components has a lost motion connection with the sector component and a fulcrum engagement with the adjacent end of said sector component whereby said live point component has a limited freedom of movement relative to the adjacent end of said sector component against the force of the corresponding live point retracting spring upon impact of said live point with a set stop pin to thereby dampen the tendency of said selecting sector assembly to rebound upon such impact.

6. In a selection mechanism including a plurality of ordinally arranged selecting sector assemblies mounted for angular movement about a common axis and each including a sector component, a live point component pivotally mounted at one end on said sector component and a live point retracting spring resiliently holding said live point component against said one end of said sector component, springs resiliently urging said selecting sector assemblies to move in one direction about said common axis, latch means releasably latching said selecting sector assemblies against movement by the last-named springs, stop pins disposed adjacent said selecting sector assemblies and selectively settable to engage said live point components and stop said selecting sector assemblies when released from said latch means at differentially set positions for the entry of selected values into said selection mechanism, and a keyboard disposed adjacent said stop pins for releasing said latch means (and selectively setting said stop pins, the arrangement wherein each of said live point components has a pin engaging nose formation spaced from the adjacent end of the corresponding sector component, a lost motion pivotal connection with the sector component spaced radially inward of the sector component from said nose formation and a fulcrum engagement with the adjacent end of said sector component between said nose formation and said pivotal connection whereby said live point component has a limited freedom 10 of rocking movement relative to the adjacent end of said sector component against the force of the corresponding live point retracting spring upon impact of said nose formation with a set stop pin to thereby dampen the tendency of said selecting sector assembly to rebound upon such impact.

7. In a selection mechanism including a plurality of ordinally arranged selecting sector assemblies mounted for angular movement about a common axis and each including a sector component, a live point component pivotally mounted at one end of said sector component and a live point retracting spring resiliently holding said live point component against said one end of said sector component, springs resiliently urging said selecting sector assemblies to move in one direction about said common axis, latch means releasably latching said selecting sector assemblies against movement by the last-named springs, settable stop pins disposed adjacent said selecting sector assemblies to engage'said live point components from thereby stop said selecting sector assemblies when released from said latch means at differentially set posi tions for the entry of selected values into said selection mechanism, and a keyboard disposed adjacent said stop pins for releasing said latch means and selectively setting said stop pins, the arrangement wherein each of said live point components has a pin engaging nose formation spaced from the adjacent end of the corresponding sector component, a lost motion pivot connection with the sector component spaced radially inward of the sector component from said nose formation, and a fulcrum engagement with the adjacent end of said sector component between said nose formation and said pivotal connection whereby said live point component has a limited freedom of rocking movement relative to the adjacent end of said sector component against the force of the corresponding live point retracting spring upon impact of said nose formation with a set stop pin, and wherein said lost motion pivotal connection is constructed to produce a sliding movement between said live point component and the adjacent end of said sector component at said fulcrum engagement therebetween to add a frictional resistance to rocking movement of said live point component relative to said selector component when said live point component is rocked in the direction in which it is urged by engagement of said nose formation with a set stop pin to thereby elfectively dampen any tendency of said selecting sector assembly to rebound upon impact of said live point component with a set stop pin.

References Cited in the file of this patent UNITED STATES PATENTS 1,091,482 Carroll Mar. 31, 1914 1,423,439 Lasker July 18, 1922 1,477,420 Breitling Dec. 11, 1923 2,427,271 Friden et al. Sept. 9, 1947 2,490,200 Boyden Dec. 6, 1949 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Non 2,886,237

Harold J0 Shall It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 70, after "Simultaneously, insert m the column 8 line 8, after "pins" strike out the comma; column 18, line 19 for "components from read components and =0 Signed and sealed this 23rd day of February 196% (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,886,237

May 12, 1959 Harold J, Chell It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should readas corrected below.

Column 5, line 70, after "Simultaneously," insert the line 8, after "pins" strike out the comma;

column 8, column 10, line 19, for "components from" read components and Signed and sealed this 23rd day of February 1965?,

(SEAL) Attest:

KARL H, AXLINE ROBERT C. WATSON Attesting Ofiicer Commissioner of Patents 

